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C. WERRA. PISTON CONSTRUCTION.

APPLICATION FILED JUNE 18. 1914.

Patentefi 22, 191

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CONRAD WERRA, OF WAUKESI-IA, WISCONSIN.

rls'ron CONSTRUCTION.

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Specification of Letters Patent.

Patented l liugfi 191%.

Application filed June 18, 1914. Serial No. 845,774.

To all whom it may concern: I

Be it known that T, CONRAD -WERRA, a citizen of the United States, and resident of Waukesha, in the county of Waukesha and State of Wisconsin, have invented new and useful Improvements in Piston Construction, of which the following is a description, reference being had to the accompanying drawings, which are a part of this specification.

This invention relates to improvements in piston construction.

Tn the manufacture of internal combustion engines the tendency is toward high speed engines which are constructed as lightly as possible. In engines of this type the cylinders and pistonsare usually formed.

- of iron and as iron is comparatively a heavy Q sion is made metal, considerable power is lost, in overcoming the inertia of movement of the heavy piston at the end of each reciprocation. ,A further objection to pistons formed of iron is that the weight causes unnecessary vibration which increases the wear on the parts and also consumes additional power.

It is one of the objects of the present in vention to overcome the before mentioned objectionable features and provide a piston construction which isof less weight than the pistons now in use and in which provifor taking the wear of the parts. I

A further object of the invention is to provide a piston construction whereby the major portion of the piston may be formed of aluminum or other light .weight metal protected with other metal at points subjected to the greatest wear.

A further object of the invention is to providea piston construction in which parts are adapted to conform to the irregularities in shape of the inner wall of the cylinder of the engine of which the piston forms a part.

' With the above and other objects in view, the invention consists of the improved piston construction and its parts and combinations as set forth in the claims, and all equivalents thereof. v

' In the accompanying drawing in which the same reference characters indicate the same parts in" all of the views: Figure 1 is a side view of a piston construction embodying the improvements Fig, 2 is a vertical central sectional view thereof taken on'line 2-2 of Fig. l; and Fig. 3 is a transverse sectional view thereof taken on line 3-3 of Fig. 1. A j

Referring to the drawing the numeral 5 indicates the body portion or shell of the piston which is formed of aluminum or other light weight metal, and is provided with the usual inwardly extending bored bosses 6 to receive the cross pin on which the connecting rod is pivotally mounted. The bosses are reinforced by ribs 7 which e2;- tend upwardly and connect with the top or end wall 8 of the piston. One of the bosses is provided with a threaded opening 9 to receive'a set screw for clamping the connecting rod cross pin in position. This end wall is of convex or crowned form to better resist the strain of the explosion. The piston is cast partly around unbroken bearing rings 10 and 11 preferably of iron which are of slightly larger diameter than the piston in order to engage the surface of the bore of the cylinder and have inner, upper and lower surfaces sufliciently smooth to prevent the body portion of the piston from adhering thereto. The rings 10 are of rectangular form in cross section and fit snugly but radially movably in the grooves 12 formed in casting the piston. tion of the bearing ring 11 is also of 'rectangular form in cross section with a flanged bearing portion 13 extending toward the open end of. the piston. This ring also fits snugly and radially movably within a groove 14: formed in casting the piston and also has inner, upper and lower surfaces sufliciently smooth to prevent the body portion of the piston from adhering thereto. The ring 11 is provided with annular grooves 15'to receive split piston packing rings of ordinary construction.

In casting the improved pistons, the rings cut to size and having smooth surfaces, are pla'cedin a die or sand mold and the molten aluminum or other light metal is then poured into the mold and engages the smooth upper, inner and lower surfaces'of the bearing rings. As the coeflicient of expansion of aluminum is greater than iron the aluminum in cooling in the mold will contract and draw radially away from the inner surfaces of the bearing rings and form in the cylinderwithout unduly straining the annular spaces l6 vvhich permits the expan sion of the piston when doing its Work With- ,rings. These annular expansion spaces also serve to permit the rings to move With relation tothe piston body andv to adapt themselves to the irregularities 'of the cylinder .bore and thus eliminate undue friction and wear. The light Weight of the piston due to the major portion being formed of aluminum requires less power to reciprocate it back and forth and vibration is reduced to a minimum. i

From the foregoing description it be seen that the piston construction provides a, light weight: piston Well adapted for the' purpose described and Which possessesthe necessary strength to Withstand the wear they are subjected to. I

What I claim as my invention is: L 1. A "piston construction, comprisingja body portion formed of a light Weight metal,

and a series of unbroken bearingrings surround nlgsaid body portion and spaced therefrom, said bearing rings being formed,

of a metal of greater Weight than the Weight of the metal of the body portion. 2. A- piston construction, comprising. a

plurality of unbroken bearing rings, and a body portion" cast Within the rings and spaced therefrom, said body portion being ing rings being greater thanfthe-outerdiam formed of a metal ofless Weight thanthe Weight offthe metal of the bearing rings. 3. A piston construction, comprising a i eter of the body portion.

, A piston construction, comprising a body portion formedofv light Weight material and provided. with-a plurality of an-.

nular grooves, and unbroken-bearing rings surrounding said body portion and entering the grooves and spaced fromsald-body portion, the outer diameter of the bearing ringsbeing greater than the outer diameter ofthe body portion, one of said bearing rings provided with an annular packing ring groove.

,5. A piston construction, comprising a body portion formed of light Weight-material and provided-with a plurality of an nular grooves, and unbroken bearing ringssurrounding said body portion and extenda diameter to permit greater expansion of the body portion than the bearing rings 6; A piston construction, comprising a body portion formed of aluminum andhaving a plurality of peripheral grooves and a.

crowned end, and unbroken bearing rings the expansion.

mounted in said grooves and spaced from the outer Walls of said grooves and engaging the side walls ther'eof'to permit greater expansion radially ofthe body -port1on, one of saidobearinglrings being provided ,With an annular-packing ring groove. 4

7; A piston, comprisingabody portion, and bearing rings non;rem ovably mounted on said body portion and spaced therefrom, thecoefficient ofiexpa-ns'ion' of the bodyportion being greater than'that of the rings and the parts being mounted to permit theex-' pansion of'said parts. .i

A piston,.comprising a body portion, and bearing rings mounted on said body por 30 tion and spaced therefrom, the. coefficient of' expansion'of the body portion being greater than that of the rings and the parts being mounted toipermit the expansion of said 'parts. a

9; A of aluminum, and bearing rings non-remov ably spaced thereon, one; of said hearing jg, ri ,gs having an annular groove'for receiving a 7 a packing rings 1.0; A.1piston,comprisinga bodyportion ofaluminum, and unbroken bearing ringsnon-removably spaced thereon, one of said bearing rings having anannular groove for receiving a packing ring,

11. In a piston" construction, the combina-. tion With a plurality of cast-iron bearing rings, of a body portion of aluminum nom' removably cast vvithin the r'ingsand spaced therefrom, the coeflicient of expansion of the body portionbeing greater than that of the. rings and the partsbeing mounted to permit 12. A piston, comprisinga body portion having a plurality of annular grooves, and

bearing rings non-reinovably mounted insaid' grooves, the'coefiiicient of expansion of the bodyportion being greater than the Y rings, the inner surfaces of said ring's being of greater diameter than the peripheries of,

the grooved portions to permit the body portion toexpand radiallyto a greater extent than the bearing rings.

'- -13 A piston, "comprising a body portion having .a pluralit'y 'of annular grooves, and bearing ringsYnon-renrovably mounted in:

said grooves, one of said r ngsprovi'ded with an annular j roove for receivinga packing ring, the coeEcient of expansion of the body I portion being greater than the bearing rings,

f the inner surfaces of said bearing rings being of greater diameter than the peripheries ing 1nt0 said grooves and spaced from said I body, portion, thegrooved portions being-of of the grooved portions to permit the body portion to expand radially "to a' greater ex-; tent than the bearing rings. 14. A piston, comprising an aluminum body portion having a plurality of annular Y grooves, and iron bearing rings non-remoy: ably mounted in said rings, one of said rings provided with an annular groove for receiv- 1 30 i i I L5 piston, comprising a body "P01131011 if I Witnesses:

In testimony whereof, I afiix my signature, n presence of two Witnesses.

CONRAD WERRA.

KATHERINE HOLT,

C. H. KEENEY. 

